US3430949A - Fabric handling machines - Google Patents

Description

March 4, 1969 D. F. HERDEG ET AL 3,430,949

FAB RIC HANDLING MACHINES Filed Sept. 18, 1967 Sheet 0f 6 Elsi Ball i F i 3 in van tars Donald FHercZEy PauZE Morgan By i/zez'r Azzor'ney arch 4, 1969 D. F. HERDEG ET AL 3,430,949

FABRIC HANDLING MACHINES Sheet Filed Sept. 18, 1967 March 4-, 1969 D HERDEG ET AL 3,430,949

FABRIC HANDLING MACHINES Sheet Filed Sept. 18, 1967 D. F. HERDEG ET L FABRIC HANDLING MACHINES March 4, 1969 Filed Sept.

' Sheet [II/Ill) N III/ll ll IIIIIIIIII/ III] I 11/ Ill/I I 3,43tl,949 FABRIC HANDLING MACHINES Donald F. Herdeg, Beverly, and Paul E. Morgan, Melrose, Mass, assignors to USM Corporation, Boston, Mass, a corporation of New Jersey Filed Sept. 13, 1967, Ser. No. 668,574 US. Qt. 2'71--63 10 (Ilairns int. Cl. 365i] 3/08, 29/00 ABSTRACT OF THE DESCLGSURE A machine for feeding fabric sheets singly from a stack of sheets or from a plurality of stacks to a work station or plurality of stations, having a novel means for controlling pick-up and release of the sheet during an operating cycle. A pick-off device and cooperating arm are effective to successively remove single plies of regular or irregular shaped fabric from a stack or selectively from one of a plurality of stacks which may be of varying heights, and deposit the ply with accuracy at a selected location during successive operations.

Background of the invention This invention relates to a device for feeding flexible sheet material and in particular to apparatus for successively feeding fabric sheets from a stack or plurality of stacks to a precise location or plurality of locations wherein the top of the stacks may be at various elevations during operation of the device.

As used herein the term fabric sheets is intended to mean all usual types of textile fabrics including woven fabrics, knit goods, non-Wovens and other air permeable textile and textile-like materials.

With an increasing need for automation in the garment, laundry and other fabric industries, various machines have been proposed in the prior art for use in the handling and transfer of fabric sheets. One such device was disclosed in US. patent application Ser. No. 647,784, filed June 21, 1967, in the name of Richard R. Walton which discloses a machine of the type wherein fabric sheets are fed singly from a stack of sheets and deposited at a precise location. The machine disclosed in this application provides novel means for effecting the release of only one sheet from the stack during each pick-off operation, and also includes a pick-off device which is effective to cleanly remove the single fabric sheet and deposit the sheet at a precise location. While the aforementioned device has proved successful in performing the desired objectives of fabric feeding from a stack to a work station, or to another stack, various detail problems are encountered in the day-to-day routine of the fabric industries, which require improvements in the previously disclosed device.

One of the more common problems which arise in the fabric handling industry is encountered where a bolt of cloth material is laid up such that alternate plies face in the opposite direction. In order to accomplish many subsequent operations it is necessary to restack the fabric sheets such that all sheets of a single stack face in the same direction. This can best be accomplished by establishing two separate stacks of fabric onto which alternate fabric sheets are stacked from the original stack of plies, one having the sheets faced in a first direction and the other having the sheets faced in the opposite direction.

Still another problem which is encountered in the fabric States Patent industry is that of precisely mating for stitching or bonding of two fabric pieces of different shape. This may be accomplished by feeding fabric pieces from two separate stacks and depositing them at a precise location at a remote work station from which the mating pieces may be transferred to a sewing machine or other fabricating device.

The present invention therefore has an object to provide a fabric handling device which will successively remove a single sheet from one or a plurality of stacks and deposit the sheet at one of a plurality of locations with great accuracy.

A further object of the invention is to provide a fabric handling device which is simple in construction and adaptable for use with a plurality of fabric stacks of various height and at various locations.

Another object of the invention is to provide a fabric handling device which will successively deposit single fabric pieces on a delivery surface with greater precision than is accomplished in prior art devices of this type.

While yet another object of the invention is to provide a fabric handling device which will deposit a single fabric sheet on a previously deposited sheet of the same or dif ferent size and shape in precise alignment, and without disturbing the underlying sheet.

Summary of the invention The various objects of the invention are achieved by providing a novel device for feeding fabric sheets singly from a stack or plurality of stacks of sheets to a work station or plurality of stacks of fabric sheets. The invention disclosed when incorporated in the preferred embodiment is useful therefore, in a variety of applications including the mating of fabric sheets for subsequent stitching or other operation, or the separation of sheets from a single stack to a plurality of stacks. In accomplishing the various objectives, the invention provides a novel pick-off device which successively removes a single sheet from one of a plurality of stacks and is effective to deposit the sheet on a surface with precision. To further increase the precision in depositing the fabric ply, the invention provides that the pick-off device be movable along the lengthwise portion of a carrier arm which incorporates means for locating, and operating on, the novel pick-ofi? device to implement precise location of the fabric piece.

The pick-off device disclosed comprises a body member having a gripping element and a stripping element, each movable relative to the body member and to each other. By employing the disclosed pick-off device a fabric piece is cleanly removed from a stack of fabric pieces, retained in precise orientation with regard to its original position on the stack, and moved to a precise location above a delivery surface which may be the top of a stack of fabric sheets, the first sheet of a pair to be mated on a work surface. To achieve the precise location of the fabric piece while depositing it on the delivery surface, the gripper element is effective to deposit the fabric piece in the precise location, after which the stripping element is moved to contact the fabric piece and hold it in the precise location. The stripping element is then retained in its holding position adjacent the receiving surface while the fabric gripping means is removed simultaneously with which the vacuum is shut off.

The pick-oft" device is thereby effective to pick up and deposit a single ply of material on top of a previously deposited ply without disturbing the underlying ply either in position or flatness without resorting to means external of the pick-off device.

To achieve a precise positioning of the pick-off elements at a predeterminined location, the invention provides a carrier arm which mounts the pick-off elements for movement along a lengthwise portion thereof. The carrier arm is provided with a plurality of means for stopping movement of the pick-off elements at precise, predetermined adjustable locations. The stopping means as disclosed include a switching means and shock absorbing element for precisely controlling the movement of the pick-off elements from one predetermined location to the other. In addition, the invention provides for moving one or more of the switching means in and out of engagement with the coacting elements to provide for the various desired stacking and unstacking sequences which are useful in the fabric handling art.

It will be understood that the particular machine embodying the invention is shown by way of illustration only and not as a limitation of the invention, as the principles and features of this invention may be employed in varied and numerous embodiments without departing from the scope thereof.

Brief description of the drawings For a more complete understanding of the invention, reference should be had to the accompanying drawings wherein:

FIG. 1 is an elevational view showing an illustrative machine embodying the invention for feeding fabric sheets singly from a plurality of stacks, to a delivery surface in accordance with the teachings of the present invention;

FIG. 2 is an elevational view showing in detail a portion of the machine of FIG. 1 made on an enlarged scale for clarity;

FIG. 3 is a top plan view showing further details of the structure of FIG. 2;

FIG. 4 is a top plan view taken along the line IV1V of FIG. 2 showing details of that portion of the machine from which the fabric sheets are fed;

FIG. 5 is a front elevational sectional view taken along the line VV of FIG. 2 showing details of the carrier arm structure of the machine taken on an enlarged scale for clarity;

FIGS. 6. 7, 8, 9 and 10 are elevational sectional views showing a pick-off device as embodied in the machine structure shown in FIGS. 1 through 5 during operation of a machine cycle and made on an enlarged scale to more clearly show the elements of the device; and

FIG. 11 is a diagrammatic view depicting the operation of the various elements of the machine shown in FIGS. 1 through 10 during a chosen cycle of the machine.

Brief description of the illustrative embodiment Referring now to the drawings especially FIGS. 1 through 3, there is shown a machine for feeding a fabric sheet in accordance with the teaching of the present invention, which includes a frame 10 having an elevator 12 mounted thereon for movement in the vertical direction. Adjacent the upper portion of the frame 10 there is fixedly mounted a carrier arm 14 extending above the elevator 12, which arm has a work head 16 slidably mounted thereon.

The elevator 12 as best shown in FIG. 1, is provided with a pair of rollers 18 and 20 disposed on opposite sides of a vertical track 22 affixed to the frame 10. The elevator 12 is further connected by a clamping member 24 to an endless chain 26, which is engaged with sprocket members 28 and 30. The uppermost sprocket member 28 is free running, and serves as an idler sprocket while the lower sprocket 30 is driven in both the clockwise and counterclockwise direction by a suitable motor means (not shown).

The elevator 12 further comprises a substantially horizontal surface 32 on which a pallet 34 hearing a stack S1 of fabric pieces (or plurality of such stacks S1 and S2) may be located with reference to the related structure to be hereinafter described.

With structure thus far described, it will be noted that movement of the sprocket member 30 in the counterclockwise direction as shown in FIG. 1 is effective to cause the elevator 12 to move upwardly along the track 22, while clockwise directional movement of the sprocket 30 is eifective to cause the elevator 12 to move downwardly.

The carrier arm 14 comprises a housing 38 having a lug 40 provided at one end thereof. The lug 40 has pivotally connected to it a cylinder 42 which extends forwardly along the length of the arm 14. The cylinder 42 is of the double acting type which may be operated by a suitable source of fluid pressure (not shown). A carriage support rod 44 is afiixed to the housing 38 at a point forward of the lug 40 and extends lengthwise along the greater portion of the arm 14.

Referring still to FIGS. 1 through 3, and in particular FIG. 3, it will be noted that the work head 16 comprises a carrier member 46 which is attached to a block 48 slidably mounted on the rod 44. The sliding block 48 and the carrier member 46 provide a carriage assembly for the various elements of the pick-off device and are movable along the rod 44 over a lengthwise portion of the carrier arm 14.

Referring still to FIG. 3 the cylinder 42 is provided with a piston rod having a pair of lugs 50 and 52. The lugs 50 and 52 are pivotally attached to the forward end of the block 48 thereby operatively connecting the cylinder 42 to the carriage assembly.

The carrier member 46 is provided with a downwardly extending portion to which a horizontally extending mounting plate 54 is attached. As will be noted, the plate 54 is further provided with a plurality of slotted openings 56 through which threaded fasteners 57 extend to support a plurality of tubular members 58. The mounting plate 54, therefore, provides an adjustable support means for the tubular members 58 which may be readily relocated in the side-by-side direction by movement of the threaded fasteners 57 in the slotted openings 56. Each of the tubular members 58 is operatively connected to a vacuum pick-off device 60, the function of which will be explained in greater detail as the description proceeds.

It will be observed, therefore, at this point in the description, that the carrier arm 14, and related work head 16 as described, are effective to provide for movement of the pick-off means 60 from the positions I or II as shown in FIG. 1 to the positions 111 or IV as shown in FIG. 2 through the function of the double acting cylinder 42 to move the carriage block 48 over a sub stantial lengthwise portion of the arm 14.

Now referring back to FIG. 1 taken together with FIGS. 2 and 4 it will be noted ,that the frame 10 is pro- 'vided with a channel bracket 62 which serves to support a vacuum hold-back means. The vacuum hold-back means device briefly, comprises a plurality of vacuum chambers 64 each operatively attached to, and pivotally supported by a rigid tubular member 66 which is in turn pivotally supported on the bracket 62. Both the construction and operation of the vacuum hold-back means is described in detail in US. patent application Ser. No. 647,784, filed June 21, 1967 in the name of Richard R. Walton, and therefore, will not be described here in detail. However, in describing the structure shown, it will be sufficent to add that the tubular members 66 are each connected to a source of vacuum which is operated continuously during operation of the machine, and that the chambers 64 are adjustable to a plurality of positions by relative movement of the tubular members 66 the brackets 62, and the pivoting freedom of the chambers 64 as mounted to the members 66.

Referring still to FIG. 4, it will be noted that a switch arm 68 extends outwardly from the bracket 62, and is attached to a limit switch LS1 which is best shown in FIG. 1. The limit switch LS1 is connected into a suitable electrical circuit and serves to control movement of the elevator 12 by controlling the drive motor means.

Referring again to FIGS. 1 through 3, it will be noted that the carrier arm 14 is provided with a plurality of stopping means located along its lengthwise portion. Each of the stopping means includes a switching means operative in an electric circuit to cut off or turn on the fluid flow to the cylinder 42 to stop, or initiate, movement of the work head '16. Additionally, the switching means provided at each of the stop locations is effective in the circuit to operate on the elevator and the pick-off elements in a manner which will be described hereinafter. While it is understood that any number of these stopping means may be used, and their location varied to achieve a desired cycle of operation, in the device shown a pair of limit switches LS2 and. LS3 are affixed to the arm 14 at the extreme ends of the length of travel desired for the work head 16 and an additional pair of movable switches LS4 and LS5 are disposed adjacent the housing 38 adjustably and mounted for movement relative thereto. The switch LS3 is provided with a shock absorbing element 70 having its plunger 72 positioned directly below the roller arm 74 of the switch LS3. Likewise, each of the movable switches LS4 and LS5 are provided with a shock absorbing element 76 and 78 respectively which are movable with the respective switch, as will be explained in detail hereinafter.

It will now be observed that the carriage block 48 is provided with an outwardly extending flange 80 having an upper surface aligned for contact with the plunger roller of the switch LS2. The flange 80 further serves to support means for contacting the other switches LS3, LS5 and LS4 in the form of threaded members 82, 84, and 86 respectively. Each of the threaded members 82, 84 and 86 are provided with a combined bumper and cam surface at one end thereof which is disposed in alignment with a respective switch and shock absorber combination. As will "be observed, the member 82 is aligned with the switch LS3, the member 84 with the switch LS5, and the member 86 with the switch LS4. As best shown in FIG. 2, the elements 82, 84 and 86 are threadedly received in the flange 80, and a locknut is provided on each of the members for retaining them in precise lengthwise orientation with regard to the carrier arm .14.

It should, therefore, be evident that by making the threaded contact elements 82, 84 and 86 each adust-able with respect to the work head 16, precise positioning of the work head with respect to the arm 14 is accomplished when a contact means registers with its respective stopping means, the switches LS3, LS4 and LS5 shutting down operation of the cylinder 42, and the shock absorbing elements 70, 76 and 7 8 serving to prevent over-travel of the head.

Referring now to FIG. 5, there is shown a typical movable stop means in the form of limit switch LS5 and its related shock absorber 78. The housing 38 is provided with a guide strip 88 which extends over a suitable length of the arm 14. Each of the movable stopping means are provided with a slide block 90 having fastening holes provided therein which may be matched with a plurality of openings provided in the guide strip for adjustably locating the movable stopping means. The slide block 90 has mounted thereon an angle strap 92 and is provided with a pair of lugs 94 and 96 for supporting a pivot rod 98. A lever arm 100 having a boss 162 disposed at one end is pivotally connected to a solenoid 104 at the opposite end such that movement of the solenoid plunger is effective to cause movement of the arm. The boss 102 is affixed to the rod 98 and has a plate 106 affixed thereto, which plate serves to support the shock absorber element 6 78. The plate 106 has an angle member .108 attached to its outer surface, on which is mounted the switch LS5. A torsion spring 109 is attached to the rod 98 and serves to rotationally bias the rod opposite to the solenoid 104.

From the structure shown in FIG. 5 it is, therefore, evident that operation of the solenoid 104 is effective to cause movement of the arm 160 which is in turn effective to move switch LS5 and shock absorber 7 8 into, or out of alignment with the contacting element 84. In like manner, the switch LS4 and related shock absorber element 76 are moved in and out of alignment with the contact element 86 through operation of a solenoid 110, the elements of that stopping means being mounted substantially as those described above.

Referring now to FIGS. 1 and 2, it will be noted that each of the pick-up heads 60 is provided with a pair of flexible pressure lines 112 and 114 attached at the opposite ends of a body portion 116. The flexible pressure lines 112 and 114 are afixed to channel members disposed on the arm 14, and are of sufficient length to permit travel of the pick-off elements 60 through the positions I through IV as shown in FIG. 2. At an intermediate point between the lines 112 and 114 the rigid tubular member 58 is attached to the body member 116 and serves to support the body member 116 as previously explained. The tubular member 58 is likewise connected to a flexible line 118 which has the opposite end connected to a manifold 12% mounted on the upper surface of the arm 14. The manifold 120 is a source of vacuum for the plurality of flexible lines 118 and is itself connected by a conduit 122 to a primary vacuum source (not shown) which may be a vacuum pump of any type well-known in the art. The conduit 122 is provided with a shut-off valve 124 which is operated by a solenoid 126. The operation of the solenoid 126 is effective to close the valve 124 to shut-off the vacuum from the manifold 120. However, as will be explained in greater detail, other vaccum shut-off means is provided at each of the pick-off elements 60 to effect precise timing of the vacuum shut-off and insure rapid release of the fabric ply at the desired location.

Referring now to FIGS. 6 through 10, there is shown a pick-off element 60 performing a typical operating sequence to pick up a single fabric ply from a stack S and deposit the ply at a delivery surface 127.

As shown in FIGS. 6 through 10, in addition to the body member 116 each of the elements 60 comprises an inner tubular member 128 having a slotted opening 130 provided in the lower wall thereof and located adjacent an opening 131 in the body member 116 which communicates with the vacuum member 58. Interposed between the body member 116 and the tubular member 128 is a stripping element 132. The stripping element 132 is of tubular construction and is provided with an opening 134 shown in registry with the opening 131 in FIGS. 6 through 8 and out of registry with the opening 131 in FIGS. 9 and 10. Both the stripping element 132 and the tubular member 128 are provided with slotted openings 136 and 138 respectively which receive a pin 140. The pin 140 is threaded into the body member 116 and extends through the slotted openings 136 and 138 to provide for non-rot-ative vertical sliding movement of the member 128 and the element 132 relative one to the other, and relative to the body member 116.

The stripping element 132 is biased in the downward direction by a helical spring 142, and pressure entering the body member 116 through the line 114 is effective to move the element 132 to the position shown in FIG. 1 where travel of the element is limited by the slotted opening 136 contacting the pin 1140. Likewise, the tubular member 128 is biased in the downward direction, as shown in FIG. 1, by a helical spring 144 to the extent that the slotted opening contacts the pin 146. Fluid pressure through the line 112 is effective to compress the spring 144 and thereby bring the tubular member 128 to the uppermost position as best shown in FIG. 7. In the embodiment shown, the gripping means for the fabric material comprises a plurality of card cloth gripping elements 146. As was disclosed in the previously cited Walton application, the card cloth elements 14-6 are effective to impale the top fabric piece when drawn into contact through vacuum which is introduced through the vacuum member 58.

For a typical pick-off and deposit operation of the element 60 reference will be made to each of the FIGS. 6 through taken in numerical order. In FIG. 6, pressure is maintained in the line 114 and pressure has been shut off in the line 112 with the resultant location of the elements 132 and 128 as shown. In response to location of the work head 16 at a predetermined position, a circuit is effective to turn on the vacuum by operation of the solenoid 126 to open the valve 124 (FIG. 1) and the top fabric ply is drawn against gripping elements 146.

The device 60 is now moved through a relatively small distance in the direction of the card cloth pick off, and after which pressure is applied to the line 112.

By pressurizing the line 112 the tubular member 128 moves to the position shown in FIG. 7, the vacuum is maintained in the tubular member 128, and the pressure is retained in the line 114 with the resultant orientation of the structure as shown in FIG. 7. Thus, the gripping elements 146 are moved upwardly with the fabric material held thereby, and the pick-off device 60 may be moved to precise location above the delivery surface 127, which may be a second stack of fabric pieces, or a work surface.

With the pick-off element so located the pressure is shut off in the line 112 and the fabric piece deposited as shown in FIG. 8.

However, to retain the fabric ply in the precise position as deposited, the pressure is next shut off at the line 114- and the stripping element 132 moves downwardly to the position shown in FIG. 9 to hold the fabric piece in contact with the delivery surface 127.

After depositing the fabric piece on the delivery surface, the valve 124 is now closed to shut off vacuum in the vacuum element 58 to effect release of the fabric piece from the gripping means 146. However, it has been found that in operating the machine through a rapid time cycle the closing off of the vacuum at a remote point from the device 60 is ineffective to instantaneously effect release of the fabric piece. In FIG. 9, therefore, it will be noted that when the stripping element 132 is moved to a position adjacent to the gripping elements 146, the opening 134 is moved out of registry with the opening 131. This causes a rapid closing off of the vacuum source to the tubular member 128 and the resultant instant release of the vacuum force on the fabric ply.

tubular member 128 is now raised by introducing pres-- sure through the line 112. This completes the release of the fabric ply from the gripping element 146, however, the ply is still retained in precise location, being held in such location bythe force of the stripping element 132 against the delivery surface 127.

The stripping element 132 is now removed from contact with the fabric ply by pressurizing the line 114 and raising the stripping element to the position shown in FIG. 6. A vent hole 149 is provided in the wall of the stripping element 132 which serves to maintain the inside of the member at atmospheric pressure and prevent the sheet from being drawn up with or otherwise disturbed by lifting of the element. This effects a clean release of the pick-off device 60 from the fabric piece deposited, leaving the fabric piece in its precise location as deposited.

While the pick-off elements 60 as described above are effective to remove a fabric piece and deposit it at a a precise location, the present invention further includes a means for moving the pick-off elements 60 to the precise location through operation of the stopping means for the switches and elements shown to effect perform-' ance through the operation as described.

Referring to FIG. 11, there is shown a schematic diagram in which the operation of the elevator 12, the carriage which moves the work head 16, the vacuum to the pick-off elements 60, and the solenoids and 104 which are effective to move the limit switches LS4 and LS5 respectively are shown. In addition it will be observed that the operation of the gripping means and stripping means through their vertical travel, as previously described, are shown in the diagram. For an understanding of the complete operation of the machine it will be assumed that a fabric stack S1 located at position I and a fabric stack S2 located at position II are each to have their separate sheets deposited on the delivery surface 127 at the position III, with an edge thereof in precise mating registration as shown in FIG. 2.

With the elevator 12 in the down position, the control circuit is energized to move the elevator up to point A as shown in the diagram where the fabric stack contacts the limit switch LS1. At that point, the vacuum is turned on by activating the solenoid 126 and a time delay in the circuit is initiated which subsequently times out to start movement of the carriage to a forward position III (B depicted in the diagram). The top fabric sheet is initially contacted by the gripping element 146 and drawn over the top surface of the stack S1 at the start of carriage movement. However, the gripping element 146 is not moved upwardly until the piece is moved from the control of the vacuum holdback chambers 64, thus preventing the non-moving chambers from interfering with the clean pick-off of the device 60. At B the carriage has moved to a position where the cam surface of the threaded contact element 84 has contacted the switch LS5 and the bumper portion has contacted the shock absorber 78. Operation of the shock absorber 78 is effective to stop motion of the cylinder 42 and stop movement of the carriage portion of the work head 16. Operation of switch LS5 initiates downward travel of the gripping means. In addition, the switch LS5 operates the related mechanism to move the switch LS4 and corresponding shock absorber 76 into position to be contacted by the contact element 86 on return travel of the carriage.

.Starting at the point B on the various diagrams the reader will observe that the carriage (after a series of built-in time delays in the circuit) is moved in the return direction, and the vacuum (after a built-in time delay) is turned off. Both the gripping means and the stripping means have their pressure lines 112 and 114 controlled by the circuit such that contact with the switch LS5 starts the gripper in a downward movement, after which the vacuum is shut off and the stripping means is also moved downwardly. As will be observed from the diagrams of FIG. 11, the circuitry with its suitable time delays is then effective to return the gripping element to the up position and shortly thereafter, to cause upward movement of the stripping means to achieve the fabric release action as described hereinbefore.

The carriage now proceeds in the return direction to position II (point C in the diagram), where contact is made between the contacting member 86 and the limit switch LS4. The limit switch LS4 is located in the circuit to stop movement of the carriage member 12, and the bumper portion of the contacting element 86 is positively stopped by the bumper 76. It will further be noted that contact with the switch LS4, as designated in time by the letter Cin the diagrams causes the elevator 12 to move in the upward direction, following which the vacuum is operated in the same sequence as previously described after forward movement of the carriage to the position III again (D in the diagrams) switch LS is again contacted and the cycle of the gripping means, the stripping means and the vacuum is again repeated.

It will now be noted that the second contact with the switch LS5 causes activation of the solenoid 110 to move the switch LS4 out of alignment with the contacting element 86. Therefore, when the carriage is now moved to the return position it will by-pass LS4, and will return to the original starting position 1 as shown in FIGS. 1 and 2.

FIG. 11 also shows a separating sequence in which a stack of fabric sheets is placed in the position II and alternate sheets are placed in positions III and IV as shown in FIG. 2. In this sequence, the circuitry is arranged such that switch LS4 remains stationary while LS5 is moved in and out of alignment with its contacting member 84.

With the elevator in the down position, the circuit is activated and limit switch LS5 and its related shock absorber 76 are moved into position. After a time delay,

the elevator 12 moves to the position where the stack contacts limit switch LS1 which is designated as point E on the diagram. At that point, the vacuum is turned on, and after a second time delay the carriage starts its forward movement. The fabric pick-off elements 60 are moved forwardly by the carriage to position III where the limit switch LS5 is activated by the carriage, which point in time is designated as point F in the various diagrams. Operation of the gripping means, the stopping means and vacuum are controlled in this circuit similarly to the previously described circuit by suitable delay means to effectively coordinate their functions with those of the pick-off elements 60. After contacting the limit switch LS5, the carriage is returned to position II (after suitable time delay) wherein contact is made with LS4 as designated by the letter G in the diagram. Operation of the limit switch LS4 is effective to cause the elevator carriage and, at a later point in time, the vacuum to operate as shown in the diagram (with the suitable time delays), however, it will be noted that at point G, the limit switch LS5 is dropped out of alignment with the contacting member 84.

On return movement of the carriage, therefore, LS5 is not contacted and at point H on the diagram, the contacting member 82 is effective to operate limit switch LS3 with the subsequent operation of the various elements as shown in the diagram.

From the foregoing therefore it will be obvious that the present machine as disclosed is capable of performing the two operations suggested with a great degree of precision. In addition, the movable stopping means in combination with the disclosed contact means are capable of being employed in the subject embodiment to perform other desired operations in the fabric handling field by providing suitable circuitry to operate the movable switches LS4 and LS5 as disclosed.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A machine for successively transferring sheets of fabric material from a stack thereof to a precise location which comprises; an elongated arm having a work head movable along a lengthwise portion thereof, said work head comprising a tubular member having an opening provided therein and fabric gripping means disposed in said opening, means for creating a vacuum in said tubular member for drawing a fabric piece into engagement with said fabric gripping means, a stripping element disposed adjacent said tubular member and spaced from said gripping means, said element and said gripping means being disposed for relative movement, means operable to move said stripping element to a position adjacent said gripping means for contacting a fabric piece engaged by said gripping means and means operable to move said gripping means relative to said stripping element and the fabric sheet so contacted by said stripping element, to thereby disengage said gripping means from the sheet.

2. The structure of claim 1 wherein said stripping element further includes means operable to close off said vacuum creating means from said tubular member by movement of said stripping element to the position adjacent said gripping means.

3. The structure as defined in claim .1 wherein said means operable to move said stripping element comprises a source of fluid pressure acting on said element to force said element in a direction and a biasing means acting on said element to force said element in a direction opposite to that of said pressure, and said means operable to move said gripping means comprises another source of fluid pressure acting on said gripping means to force said gripping means in a direction and another biasing means acting on said gripping means in a direction opposite from said other fluid pressure source.

4. A machine for successively transferring sheets of fabric material from a stack thereof to a precise location on a delivery surface comprising; an elongated arm having a work head movable along a lengthwise portion thereof, said work head comprising a body member having a gripping means, disposed thereon for engaging a fabric sheet and movable relative to said body member, means for moving said gripping means relative to said body member to deposit a fabric sheet engaged thereon at a precise location on the delivery surface and means disposed on said body member for contacting the fabric sheet and retaining it at the precise location while said gripping means is moved relative to said body member to thereby disengage the fabric piece from said gripping means.

5. The structure of claim 4 wherein said means for contacting the fabric piece and retaining the piece at the precise location comprises a stripping element disposed on said body member and movable relative thereto.

6. The structure of claim 5 wherein said work head further comprises a tubular member movable relative to said body member and having an opening provided there in, said fabric gripping means being disposed in said opening, and means for creating a vacuum in said tubular member for drawing a fabric piece into engagement with said gripping means, said fabric gripping means being connected to said tubular member and movable therewith relative to said body member. 7

7. The structure of claim 6 wherein said stripping element comprises a tubular portion concentrically located with respect to said vacuum tubular member.

8. The structure of claim 4 which further comprises means operative for moving said work head along a lengthwise portion of said arm, a plurality of means for stopping movement of said work head each positioned at a different location along the lengthwise portion of said arm, and means readily adjustable in the lengthwise direction disposed on said work head for contacting one of said stopping means to effect precise location of said work head along the length of said arm when said work head is stopped by said stopping means.

9. The structure of claim 8 wherein each of said stopping means comprises a switch for terminating operation of said work head moving means and a shock absorbing element disposed adjacent thereto, and said readily adjustable means comprises a member having a cam aligned for contact with said switch and a bumper surface aligned for contact with said shock .absorbing element.

10. The structure of claim 4 which further comprises means operative for moving said work head along a lengthwise portion of said arm, first stopping means, intermediate stopping means and second stopping means each positioned at a different location along the length- 1 1 1 2 wise portion of said arm and separate means disposed on References Cited said work head for contacting each of said first, inter- UNITED STATES PATENTS mediate, and second stopping means, each of said stoping means being disposed in alignment for contact with 2,341,521 2/1944 Baker 27126 its respective contacting means, and said intermediate 2,737,389 3/1956 Evans 271 48 5 3,132,858 5/1964 Bernard 271 74 stopping means being movable to a position out of alignment with its respective contacting means, and means operatively connected with said second stopping means to RICHARD AEGERTER "nary Examme' alternately move said intermediate stopping means into US Cl XR and out of said alignment when said second stopping 10 means is contacted by said second contacting means.

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